The present invention relates to laser texture processing apparatus and method, and more particularly to laser texture processing apparatus and method for applying texture processing to a contact start and stop zone of a hard disc using a laser beam.
Such a kind of conventional laser texture processing apparatus or method is used for manufacturing the contact start and stop zone by applying a condensed laser beam to a limited range of a surface of the hard disc to melt the surface in the limited range and forming hundreds of thousands of minute ring-shaped projections (referred to as bumps, hereinafter) having a constant height of 100-300 .ANG..
FIG. 4 is a schematic view showing an arrangement of a conventional laser texture processing apparatus.
The laser texture processing apparatus has a laser beam source 21, lenses 23 for condensing a laser beam on a surface of a hard disc 22, a beam attenuator 24 for attenuating power of the laser beam applied to the hard disc 22 and controlling the power so as to be predetermined power, a linear stage 25 for carrying the laser beam source, the lenses and the beam attenuator and moving in a direction along a radius of the hard disc 22, and a spindle 26 for rotating the hard disc. Height of the bumps can be changed by varying the power of the laser beam or varying a pulse width of the laser beam by means of the beam attenuator 24.
However, as the diameter of the bump to be formed is smaller, an amount of the change (referred to as processing sensitivity, hereinafter) of height of the bump to an amount of the change of an output value of the laser height, and since the height of the bump is remarkably effected by stability of the laser beam, there is a task that it is much difficult to form the bump having uniform height in the prior art.